Late Holocene explosive activity of the Atsonupuri volcano (Iturup Island, Southern Kuril Islands): preliminary results

The first results of the study of Late Holocene activity of the Atsonupuri volcano (Iturup Island, Southern Kuril Islands) obtained during field work in 2013–2014 are presented. On the basis of tephrochronological studies and radiocarbon dating, it was established that at least 4 large explosive (explosive-effusive) eruptions (individual major eruptions or series of eruptions close in time) were recorded in the interval 1400–800 years ago. The period of intense explosive activity of the volcano was followed by a period of quiescence beginning around 500–600 BP and continuing to the present, as evidenced by the lack of documented eruptions in historical time. The material composition of the juvenile tephra of the Atsonupuri volcano, represented mainly by cinder, corresponds to moderate- and low-potassium basalts and andesite-basalts. Based on the data obtained, it can be assumed that in case of renewed activity of the volcano not only terminal (subterminal) eruptions but also side eruptions are probable.